compositor

compositor

Properties

Types and Values

Object Hierarchy

    GObject
    ╰── GInitiallyUnowned
        ╰── GstObject
            ╰── GstElement
                ╰── GstAggregator
                    ╰── GstVideoAggregator
                        ╰── GstCompositor

Implemented Interfaces

GstCompositor implements GstChildProxy.

Description

Compositor can accept AYUV, ARGB and BGRA video streams. For each of the requested sink pads it will compare the incoming geometry and framerate to define the output parameters. Indeed output video frames will have the geometry of the biggest incoming video stream and the framerate of the fastest incoming one.

Compositor will do colorspace conversion.

Individual parameters for each input stream can be configured on the GstCompositorPad:

  • "xpos": The x-coordinate position of the top-left corner of the picture (gint)
  • "ypos": The y-coordinate position of the top-left corner of the picture (gint)
  • "width": The width of the picture; the input will be scaled if necessary (gint)
  • "height": The height of the picture; the input will be scaled if necessary (gint)
  • "alpha": The transparency of the picture; between 0.0 and 1.0. The blending is a simple copy when fully-transparent (0.0) and fully-opaque (1.0). (gdouble)
  • "zorder": The z-order position of the picture in the composition (guint)

Sample pipelines

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gst-launch-1.0 \
  videotestsrc pattern=1 ! \
  video/x-raw,format=AYUV,framerate=\(fraction\)10/1,width=100,height=100 ! \
  videobox border-alpha=0 top=-70 bottom=-70 right=-220 ! \
  compositor name=comp sink_0::alpha=0.7 sink_1::alpha=0.5 ! \
  videoconvert ! xvimagesink \
  videotestsrc ! \
  video/x-raw,format=AYUV,framerate=\(fraction\)5/1,width=320,height=240 ! comp.
A pipeline to demonstrate compositor used together with videobox. This should show a 320x240 pixels video test source with some transparency showing the background checker pattern. Another video test source with just the snow pattern of 100x100 pixels is overlaid on top of the first one on the left vertically centered with a small transparency showing the first video test source behind and the checker pattern under it. Note that the framerate of the output video is 10 frames per second.
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gst-launch-1.0 videotestsrc pattern=1 ! \
  video/x-raw, framerate=\(fraction\)10/1, width=100, height=100 ! \
  compositor name=comp ! videoconvert ! ximagesink \
  videotestsrc !  \
  video/x-raw, framerate=\(fraction\)5/1, width=320, height=240 ! comp.
A pipeline to demostrate bgra comping. (This does not demonstrate alpha blending).
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gst-launch-1.0 videotestsrc pattern=1 ! \
  video/x-raw,format =I420, framerate=\(fraction\)10/1, width=100, height=100 ! \
  compositor name=comp ! videoconvert ! ximagesink \
  videotestsrc ! \
  video/x-raw,format=I420, framerate=\(fraction\)5/1, width=320, height=240 ! comp.
A pipeline to test I420
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gst-launch-1.0 compositor name=comp sink_1::alpha=0.5 sink_1::xpos=50 sink_1::ypos=50 ! \
  videoconvert ! ximagesink \
  videotestsrc pattern=snow timestamp-offset=3000000000 ! \
  "video/x-raw,format=AYUV,width=640,height=480,framerate=(fraction)30/1" ! \
  timeoverlay ! queue2 ! comp. \
  videotestsrc pattern=smpte ! \
  "video/x-raw,format=AYUV,width=800,height=600,framerate=(fraction)10/1" ! \
  timeoverlay ! queue2 ! comp.
A pipeline to demonstrate synchronized compositing (the second stream starts after 3 seconds)

Synopsis

Element Information

plugin

compositor

author

Wim Taymans <wim@fluendo.com>, Sebastian Dröge <sebastian.droege@collabora.co.uk>

class

Filter/Editor/Video/Compositor

Element Pads

name

sink_%u

direction

sink

presence

request

details

video/x-raw, format=(string){ AYUV, BGRA, ARGB, RGBA, ABGR, Y444, Y42B, YUY2, UYVY, YVYU, I420, YV12, NV12, NV21, Y41B, RGB, BGR, xRGB, xBGR, RGBx, BGRx }, width=(int)[ 1, 2147483647 ], height=(int)[ 1, 2147483647 ], framerate=(fraction)[ 0/1, 2147483647/1 ]

name

src

direction

source

presence

always

details

video/x-raw, format=(string){ AYUV, BGRA, ARGB, RGBA, ABGR, Y444, Y42B, YUY2, UYVY, YVYU, I420, YV12, NV12, NV21, Y41B, RGB, BGR, xRGB, xBGR, RGBx, BGRx }, width=(int)[ 1, 2147483647 ], height=(int)[ 1, 2147483647 ], framerate=(fraction)[ 0/1, 2147483647/1 ]

Functions

Types and Values

struct GstCompositor

struct GstCompositor;

The opaque GstCompositor structure.


enum GstCompositorBackground

Members

COMPOSITOR_BACKGROUND_CHECKER

   

COMPOSITOR_BACKGROUND_BLACK

   

COMPOSITOR_BACKGROUND_WHITE

   

COMPOSITOR_BACKGROUND_TRANSPARENT

   

Property Details

The “background” property

  “background”               GstCompositorBackground

Background type.

Flags: Read / Write

Default value: Checker pattern